Create case

 import javax.net.ssl.*;

import java.io.*;

import java.net.HttpURLConnection;

import java.net.URL;

import java.net.ProtocolException;

import java.net.MalformedURLException;

import javax.net.ssl.HostnameVerifier;

import javax.net.ssl.HttpsURLConnection;

import javax.net.ssl.SSLContext;

import javax.net.ssl.SSLSession;

import javax.net.ssl.TrustManager;

import javax.net.ssl.X509TrustManager;

import java.security.KeyManagementException;

import java.security.NoSuchAlgorithmException;

import java.security.cert.X509Certificate;

public class Main {

    static String createCase() throws IOException, NoSuchAlgorithmException, KeyManagementException {

        String caseId=null;

        String messageContent = "";

        BufferedReader br = new BufferedReader(new FileReader(new File("CreateCase.json")));

        String line=null;

        while((line=br.readLine())!= null){

            messageContent += line;

        }

        // Printing the message

        System.out.println(messageContent);

        // URL of the API or Server

        String url = "<<URL>>";

        URL urlObj = new URL(url);

        TrustManager[] trustAllCerts = new TrustManager[] {new X509TrustManager() {

            public java.security.cert.X509Certificate[] getAcceptedIssuers() {

                return null;

            }

            public void checkClientTrusted(X509Certificate[] certs, String authType) {

            }

            public void checkServerTrusted(X509Certificate[] certs, String authType) {

            }

        }

        };

        // Install the all-trusting trust manager

        SSLContext sc = SSLContext.getInstance("SSL");

        sc.init(null, trustAllCerts, new java.security.SecureRandom());

        HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());

        // Create all-trusting host name verifier

        HostnameVerifier allHostsValid = new HostnameVerifier() {

            public boolean verify(String hostname, SSLSession session) {

                return true;

            }

        };

        // Install the all-trusting host verifier

        HttpsURLConnection.setDefaultHostnameVerifier(allHostsValid);

        HttpsURLConnection postCon = (HttpsURLConnection) urlObj.openConnection();

        //postCon.setSSLSocketFactory(SSLCertificateSocketFactory.getInsecure(0, null));

        //postCon.setHostnameVerifier(getHostnameVerifier());

        postCon.setRequestMethod("POST");

        // Setting the message content type as JSON

        postCon.setRequestProperty("Content-Type", "application/json");

        postCon.setDoOutput(true);

        // for writing the message content to the server

        OutputStream osObj = postCon.getOutputStream();

        osObj.write(messageContent.getBytes());

        // closing the output stream

        osObj.flush();

        osObj.close();

        int respCode = postCon.getResponseCode();

        System.out.println("Response from the server is: \n");

        System.out.println("The POST Request Response Code :  " + respCode);

        System.out.println("The POST Request Response Message : " + postCon.getResponseMessage());

        if (respCode == HttpURLConnection.HTTP_CREATED)

        {

        // reaching here means the connection has been established

        // By default, InputStream is attached to a keyboard.

        // Therefore, we have to direct the InputStream explicitly

        // towards the response of the server

            InputStreamReader irObj = new InputStreamReader(postCon.getInputStream());

            br = new BufferedReader(irObj);

            String input = null;

            StringBuffer sb = new StringBuffer();

            while ((input = br .readLine()) != null)

            {

                sb.append(input);

            }

            br.close();

            postCon.disconnect();

            // printing the response

            String strResponse=sb.toString();

            caseId=strResponse.substring(strResponse.indexOf(" ")+1,strResponse.indexOf("\","));

        }

        else

        {

            // connection was not successful

            System.out.println("POST Request did not work.");

        }

        return caseId;

    }

    private static HostnameVerifier getHostnameVerifier() {

        HostnameVerifier hostnameVerifier = new HostnameVerifier() {

            @Override

            public boolean verify(String hostname, SSLSession session) {

                HostnameVerifier hv =

                        HttpsURLConnection.getDefaultHostnameVerifier();

                return hv.verify("com.example.com", session);

            }

        };

        return hostnameVerifier;

    }

    public static void main(String[] args) throws IOException, NoSuchAlgorithmException, KeyManagementException {

        String caseId = createCase();

        System.out.println("CaseId="+caseId);

    }

}

################CreateCase.json################

{

  "caseTypeID": "ING-WB-PAM-Work-BillableAgreement",

  "content": {

    "Country":"CzechRepublic",

    "AccountDetails":{

      "AccountBIC":"INGBCZPPXXX",

      "AccountName":"NABUURS S.R.O.",

      "AccountNumber":"",

      "AccountStartDate":"20170424",

      "AccountStatus":"O",

      "AccountType":"CACC",

      "BankCode":"3500",

      "Currency":"CZK",

      "StartDate":"20170424T000000.000 GMT",

      "SubAccountType":""

    },

    "AccountIdentifiers":{

      "BBAN":"CZ1535000000001000427519",

      "Currency":"CZK",

      "IBAN":"CZ1535000000001000427519"

    },

    "GridDetails":{

      "GRIDID":"479527870",

      "IBSSRNr":"",

      "pyID":"47952787"

    }

  }

}